The present invention relates to a cutting tool for metal cutting with a cutter with parallel base surfaces and grooves machined into the side surfaces, forming cutting edges. This cutter can be inserted into the recesses of a tool holder, has a center bore for accommodating a clamping element, and is made from a parallelepiped-shaped base body with rectangular and preferably square sides.
The invention is based on the concept that there are known in the art metal-cutting tools consisting of a support or holding body which is mounted adjustably in the support of a machine tool facing the workpiece to be machined. The actual cutter, has one or several cutting edges for the removal of chips, and is mounted in a disconnectable manner on the free end of this tool holder. The shape of the cutter, in particular its geometry, corresponds to the machining operation to be performed.
In one of these known embodiments of cutting tools, the cutter has the form of two truncated pyramids attached by their top surfaces with the square base surfaces parallel to each other; their outside edges may run parallel or may form an angle of up to 10.degree. with one another, depending on how the associated cutting tool is to be used.
For example, it is absolutely necessary that the truncated-pyramid-like cutter halves are displaced by a certain angle relative to one another if one wants to prevent that the cutter base surface comes in contact with the machined workpiece when turning right-angle shoulders.
Since, however, the amount of displacement angle, depending on the desired chip formation, must be different, the use of these known cutters requires the holding in readiness of such cutters with displacement angles of varying size. It also requires the use of differently shaped tool holders, in view of the arrangement of the recess walls (serving as supporting surfaces) or the use of two additional supports with curved outside surfaces, mounted on the tool holder. In addition, their manufacture, due to the number and mutual alignment of numerous ways of grinding is very cumbersome.
It is, therefore, an object of the present invention to provide a cutter which has four positive edges with which the operations turning, milling and copying can be carried out precisely without damage to the cutting edges used, when using the same cutter tool holder. Its geometry permits the simple manufacture of a left-hand or right-hand cutter, each with four positive cutting edges, from the same blank.
Another object of the present invention is to provide a cutter of the foregoing character which may be simply fabricated and have a long service life.